The New Technology Research And Development On Advanced Treatment Of The Cyanide Wastewater

This paper first introduces the wastewater sources of Daqing Petrochemical Company which mainly contains acrylonitrile and acrylic fiber industrial water and then describes the process mechanisms and procedures for two sets of cyanogen containing wastewater producing manufacturing and current disposing devices. The purpose, meaning and studying area of this paper is determined for the existing sub-standard effluent with a CODcr value of 300mg/L which cannot be discharged.Based on the current technology ofcyanide containing wastewater treatment in and out, the research baseline has been set up. By targeting the effluent of current cyanide containing wastewater treatment facilities, transition metal, ozone-enhanced photocatalysis advanced oxidation andmicro-aerator trickling filtershave been applied for the purpose of cyanide containing wastewater advanced treatment. The treated wastewater achieved, if not better than the nation discharging standard(CODcr≤150mg/L). In order to preliminarily verify the treatment result, the lab-test has been conducted. The effect of p H, concentration of transition metal ion, water temperature, ozone concentration and UV intensity on CODcr removing rate ofcyanidecontaining wastewater has been studied intransition metal ion and UV catalysis ozone oxidation advanced oxidation process. We also studied the synergistic effect and biological characteristics between adsorption of microbial carrier such as ceramsite, active carbon and fly ash and specific biological membrane biodegradation. The reaction mechanisms of transition metal ion and UV catalysis ozone oxidation advanced oxidationand optimal conditions ofmicro-aerator trickling filter have been further understood. Thus, the foundation for in-situ pilot test has been laid. The in-situ test process units have been determined, which consist of sand-filtration pre-treatment unit, transition metal ion and UV catalyst ozone advanced oxidation unit and micro-aerator trickling filter unit. Operating stage was after the setup of in-situ test, debugging and sludge acclimation. The continuous tests based on month for parameters variation were conducted; the impacting simulation test stage was in the last month. The result of five-stage in-situ tests showed transition metal ion, UV catalysis ozone advanced oxidation and micro-aerator trickling filter have a good degrading and removing effect. They also have an outstanding impact resistance which can stably meet thecyanide containing discharging standard. The optimal ratio of composite coagulates is 20mg/L of polyaluminium ferric chloride(PAFC) and diatomite, respectively. The best loading of Fe2+ is 0.01kg/h, with ozone loading not less than 80mg/L, UV intensity not less than 1KW and the hydraulic retention time for micro-aerator trickling filter unitnot less than 7 hours. This industrial application technological cost for investigation in Daqing Petrochemical Company is about 89.5069 million RMB. The operation cost increase is 2.15 RMB per ton of wastewater proximately if advanced treatment facility is added.